package com.hmdp.utils;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Component;

import javax.annotation.Resource;
import java.time.LocalDateTime;
import java.time.ZoneOffset;
import java.time.format.DateTimeFormatter;

@Component
public class RedisIDWorker {
    private static final long BEGIN_TIMESTAMP = 1640995200L;
    private static final int COUNT_BITS = 32;

    @Resource
    private final StringRedisTemplate stringRedisTemplate;

    public RedisIDWorker(StringRedisTemplate stringRedisTemplate) {
        this.stringRedisTemplate = stringRedisTemplate;
    }

    public long nextId(String keyPrefix){
        // 1.生成时间戳
        long now = LocalDateTime.now().toEpochSecond(ZoneOffset.UTC);
        long timeStamp = now - BEGIN_TIMESTAMP;

        // 2.生成序列号
        // 2.1获取当前日期，精确到天
        String format = LocalDateTime.now().format(DateTimeFormatter.ofPattern("yyyy:MM:dd"));
        long increment = stringRedisTemplate.opsForValue().increment("incr:" + keyPrefix + ":" + format);

        // 3.拼接并返回
        return timeStamp << COUNT_BITS | increment;
    }
}

